US1380706A - Centrifugal switch - Google Patents

Description

A. N. EDEBURN.

CENTRIFUGAL SWITCH.

l N ILED NOV. 4, I9l9.

Patented J une 7, 1921.

SHEETS-SHEET l.

AN. EDEBUFN rA'rNr ALFRED N. EDEBURN, F CLEVELAND, OHIO.

CENTRIFUGAL SWITCH.

Specification of Letters Patent.

Patented ll une 7, i921.

Application led. November 4, 1919. Serial No. 335,627.

To all w 710m t may concern f Be it known that I, ALFRED N. EDEBURN, citizen of the United States, residing .at Cleveland, in the county of Cuyahoga and State of Ohio, have invented' certain new and useful Improvements in Centrifugal Switches, of which the following is a specilication.

This invention relates to a centrifugal snap switch, and the invention is particularly applicable to that type of electric motor wherein exciting fields are used to start the motor and an automatic switch is employed to cut out the exciting fields after the motor has been started and is revolving rapidly. In general my object is to provide a centrifugal switch which is particularly constructed to effect breakl of contact with a snap or instantaneous action so as to prevent arcing, thereby providing a switch of special utility for motors of high power. The switch is also constructed with an equalizing ring to maintain good contact when the switch is closed, and the body of the switch is providedwith fan blades adapted to circulate air through the motor.

In the drawings accompanying this application, Figure l is a plan view of a motor, partly in section, showing my invention incorporated therein. Fig. 2 is an end view of the switch and interior of the motor, the end cap of the motor being removed. Fig. 3 is an enlarged view of the switch in section and a part of the motor, showing the switch in a closed position as occurs when the motor is not in operation. Fig. 4 is a similar view to Fig. 3, but showing the centrifugal release and resetting members moved outwardly with the release member at the point where a break in contact is about to be effected. Fig. 5 is a view corresponding to Figs. 3 and 4, but with the switch in the open position which is maintained as long as the motor is running. Fig. 6 is a bottom View and cross section of the parts on line 6 6, Fig. 3, and Fig. 7 is a section transversely of the same parts on line 7 7, Fig. 3. Fig. 8 is a plan section on line 8 8, Fig. 7. Figs. 9 to 13, inclusive, are perspective views of separate elements of the switch.

The invention comprises a motor 2 embodying exciting fields 3, an armature shaft 4, a cover or cap 5, and a pair of stationary contact members 6 and 7 electrically connected with the exciting fields 3 and fixed on opposite sides of the shaft upon an insulat-A ing plate 8 within the inside of the cover or cap, see Fig. 1. i

A metal ring 9 engages the contact members 6 and 7 whenever shaft 4 is at a standstill or revolving at slow speed, and this ring is insulated from the shaft although rotated thereby. This ring is also loosely mounted to establish an equalizing wiping contact with both contact members, and the support for the ring is movable longitudinally of the shaft to make and break the contact. Thus, ring 9 is made slight-ly fiaring or wedge shape, and is seated upon an insulating base piece 10 which together with the ring is clamped within the border flange 11 of an annular disk 12. This disk fits loosely over a cylindrical plunger or sleeve 14 between a collar 15 fixed on the extreme end of the sleeve and a coiled spring 16 encircling the cylindrical body of the sleeve, and the sides of sleeve 14 are slotted lengthwise'toI receive projections 17 on the inner edge of disk 12 whereby the disk is caused to rotate with the sleeve but is also free to slide vand assume different angular positions within limits in respect to the sleeve and the two contacts.

Sleeve 14 is slidably supported on the round extension 18 of a compartmented body 19 pinned to the motor shaft 4, and aI short coiled spring 2O is confined within sleeve 14 in bearing engagement with a fixed collar 21 on the outer end of extension 18, whereby constant pressure is exerted upon the sleeve to slide it in a direction away from the contact members 6 and 7. However, an inward movement of the sleeve away from the contact members is prevented byy a pair of centrifugal members 22 and 23 respectively, when the shaft is' idle or revolving slowly. Under such conditions a lateral lug .24 at the inner ends of sleeve 14 is adapted to bear against the flat step or narrowed extremity 25 of centrifugal member 22 which is slidably seated in a channel or compartment 26 in body 19 at one side of its axis. A coiled spring 26 within this compartment presses member 22 toward the shaft and holds extremity 25 opposite lug 24 until the shaft revolves at high speed and member 22 is moved outward by centrifugalforce. In this interval of movement of member 22 the other and heavier centrifual member 23 located on the opposite side of the shaft within a second and larger chair ioo iio

nel or compartment 27 in body 19 is also moving outwardly under centrifugal force and counter to the action of its coiled spring 28. Member 23 is provided with beveled ends or prongs 29 opposite the inner end of sleeve 14 and when the motor slows down and stops their particular function is to press the sleeve outward and close the switch, or in other words, to set the parts for starting the motor as shown in Fig. 3. Mani-j feStly, the beveled ends 29 of centrifugal member 28 must be withdrawn coincident with the withdrawal of extremity 25 of the other centrifugal'member 22, and preferably, in advance thereof so that the sleeve 12 may move inwardly without hindrance the moment the right-angled corner of eX- tremity 25 lis disengaged from the rightangled corner of lug 24 on the sleeve. This working position of parts is shown in Fig. 4 where the sleeve is still held against inward movement by vlug 24 but about to be released. When released, spring 16 snaps the sleeve to the left and breaks the contact instantly between conducting ring 9 and the two conducting contact members G and 7 see Fig. 5, where the movable parts are .assumed to be operating under a high speed of revolution of shaft 4.

The inner straight-edged enlargement of plunger sleeve 14 of which lug 24 forms a part operates back and forth between the two compartmented offsets 30 of body 19, 'and the sleeve is free to slide therebetween but cannot turn i' dependently of body 19. A separate plate 3l of arcuate shape having a lip 32 closes the front side and end of each compartment, and radial flanges 33 on each plate function as fan blades to circulate air through the motor when the shaft and switch body 19 revolve.. 'This body being of unequal size on opposite sides of the shaft l provide balancing pieces 34 outside of the smaller compartment 26, and fasten fan plate 31 and these pieces to the wall of bodyI 19 'by screws 35, see Fig. 8.

Briefly summarizing, when the motor is idle the switch is closed and the exciting fields are in circuit to enable the motor to be easily started. When the shaft revolves at high speed, lug 24 is released by the final .outward movement of centrifugal member 22, and the switch flies open. When the main circuit of the motor isswitched ofi' the motor ceases to run and the centrifugal members are returned to theiroriginal starting position. In this centripetal movement the beveled ends 29 of centrifugal member 23 force sleeve 14 outwardly until ring 9 is again in contact with the contact members 6 and 7 and the right-angled extremity 25 of the other centrifugal member 22 is behind lug 24 as at the beginning.

What I claim is:

l. A centrifugal switch, comprising sepsai'd members.

2. A'centrifugal switch, comprising separable contact members, a spring adapted to 'sepa-rate said members quickly, a centrifugal element adapted to check the action of said spring, and a spring-pressed centripetallymovable.element adapted to compress said spring and maintain contact between said members.

3. A centrifuga-l switch, comprising separable c'ontact members, and a pair of independently acting springs and centrifugally acting elements adapted to separate said contact membersv quickly and to'restablish contactl therebetween. alternately.

4. A centrifugal switch, comprising a stationary contact member and a rotatable contact member, a .spring adapted to press said members into contact, a centrifugal element adapted in one of itspositions of r-est to hold said spring under compression, and a second spring adapted -to separate said contact members upon shift' of-.position of said centrifugal element.

5. A centrifugal switch, comprising separable contafct members,. a spring-pressed slidable support for one of said members, a rotatable mounting for said support carrying a centrifugal element separably engaged with said slidable support, andself-actmg means adapted to reverse the movement of said slidable support.

6. A centrifugal switch, comprising separable contact members, a rotary body having a spring-pressed plunger thereon adapted to .separate .said members. a centrifugal element carried 'by said body adapted to arrest the movement of said plunger in one direction and a centripetally-movable device adaptedto shift said plunger in the opposite direction to bring said members into contact.

7. A centrifugal switch, comprising a rotatable body, a spring-pressed plunger mounted upon said body, a pair of springpressed centrifugal elements, one element being adapted to check the movement of the plunger and the other element to move the plunger, a contact ring mounted upon said plunger, and a contact member adapted to.

be engaged by said ring.

8. A centrifugal switch, comprising a compartmented body having separate sprlngpressed centrifugal elements therein, a spring-pressed plunger opposite said ele' ment-s, one-of said elements having a rightangled extension adapted to arrest the movement of the plunger in one direction and the other element having a beveled portion adapted to press the plunger in the opposite insonne direction, and separable electrical contact members adapted to open and close an electric circuit by and through the movement of said plunger.

9. A centrifugal switch for electric mct-ors, comprising separable contact members, and a pair of independently-acting centrifugal elements adapted to separate said members and bring them into contact alternately.

10. A centrifugal switch for electric motors, comprising separa-ble contact members,

a centrifugally-acting element and spring`v adapted to separate said members instantly, and a.. slower centrifugal latch element adapted to bring said members into contact.

11. A centrifugal switch for electric motors, comprising a set of separable contact members adapted to open and close an electric circuit, a spring-pressed centrifugal latch element adapted to eil'ect instant separation of said members, and a second springpressed centrifugal latch element of lesser weight than said first element adapted to bring said members into contact.

12.` An electric switch, comprising a revoluble body having a centritugally-acting element and a spring-pressed plunger mounted thereon in coperating engagement, a contact member stationed opposite said plun ger, and a rotatable contact member having an equalizing connection with said plunger.

13. In an electric switch, a revoluble body having a centrifugal-acting element thereon, a spring-pressed plunger adapted to be Withheld from movement by said element, a spring-pressed contact member loosely mounted upon said plunger, and a second contact member stationed in engaging position opposite said first member.

14. An electric switch for motors, comprising a revoluble lbody, a slidable plunger -having a contact member mounted thereon,

a centriugally-acting element having a y right-angled extremity engaged with said plunger, a second spring-pressed centrifugally-acting element having a beveled eX- tremity engaged With said plunger, a spring adapted to move said plunger against said elements, and a second -contact Imember stationed opposite said lirst -contact member.

15. A centrifugal switch for an electricl 16. A centrifugal switch for an electric motor, comprising a revoluble body having a round extension with a collar, a plunger and a coiled spring sleeved upon said extension, a centrifugallyacting element adapted to arrest the movement of said plunger, a contact member loosely connected with said plunger, and a second contact member stationed opposite said lirst contact member.

17. A centrifugal switch for an electric motor, comprising a revo-luble compartmented body having a cylin-drical extension, separate centrifugally-acting elements and springs Within the compartments of said body, a plunger sleeved upon said extension in engagement With the inner extremities of said elements, a spring adapted to pressthe plunger toward said elements, an annular disk loosely mounted upon said plunger, a backing spring for said disk, a contact ring mounted in insulated position upon said disk, and separate contact members stationed opposite said ring.

Signed at Cleveland, in the county of Cu ahoga, and State of Ohiogthis 3rd day of -Tovember, 1919.

ALFRED N. EDEBURN.

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